LAS VEGAS — As incredible as the first fight between Diego Corrales and Jose Luis Castillo was last May, won by Corrales in shocking fashion via 10th-round technical knockout, the events that took place Friday as a prelude to tonight’s rematch were nearly as stunning.

Castillo failed to make the 135- pound weight limit on three attempts, and a member of his entourage, Armando Barak, was caught red-handed trying to tamper with the scale on the second attempt.

Here are the repercussions: Corrales’ World Boxing Council and World Boxing Organization lightweight belts, which were to be at stake, are now not on the line. The main event at the Thomas & Mack Center will still go on, but as a non- title fight. Showtime will televise on pay-per-view for $44.95.

Castillo was fined $120,000, or 10 percent of his $1.2 million purse. Half will be added to Corrales’ $2 million purse, half will go to the Nevada State Athletic Commission.

Barak was cited by the commission and will not be allowed to work Castillo’s corner. Further sanctions on Barak could be forthcoming.

Late Friday, promoters Bob Arum and Gary Shaw were trying to come to terms on what Castillo will be allowed to weigh in at today. Arum, who promotes Castillo, was negotiating for 147 pounds. Shaw, who promotes Corrales, wants Castillo to weigh in at no more than 146, or face further punishment.

Either way, this is now a welterweight fight.

Castillo, 31, of Mexico, was obviously very weak as he was being led up the stairs to the scale. After he got on and off quickly the first time, he weighed in at 137.

The second time, during a more reasonable stay on the scale, Barak was caught sticking his foot under the scale so as to push it up, which would make the scale show a lower weight. He was banished from the proceeding. Castillo, who was given two hours to make weight after the first try, gave up 1 1/2 hours later after a third failed attempt. He weighed 138 1/2 on the second and third tries.

Interestingly, Arum said that in his mind, all of this does not put a damper on what should still be a heck of a fight.

Castillo was not made available for comment Friday. But Joe Goossen, who trains Corrales, said these events would not change how he and Corrales approach tonight’s fight.

“He looked horrible,’ Goossen said of Castillo. “It looked like there was nothing left for him to lose. He was literally being carried up the steps to the scale.

“Psychologically, he has to be feeling horrible. But I don’t think we will make any adjustments based on this. I think we are still going to go with what we came with.’

Goossen has not divulged any strategy for the rematch. Many experts have wondered if, considering the vicious nature of their first fight, would there be more boxing and less toe-to-toe action tonight?

Not likely, Goossen said.

“Neither one of these guys knows how to back up,’ he said.

Even though Corrales won the first fight, getting up from two 10th- round knockdowns in a display of rare courage, he appeared to have taken a worse beating than did Castillo.

Corrales’ face was a grotesque mask of purple lumps and bruises. He said he expects more agony tonight.

“I honestly believe that I have to be prepared to go through the exact same thing again,’ said Corrales, 28, of Sacramento. He is 40-2 with 33 knockouts.

“I just put it in my head, `Screw it, this is what it’s going to be. It’s going to hurt. Let’s do it,’ ‘ he said.

Castillo, in the days leading to Friday’s meltdown, talked about trying to perhaps dodge some of the bullets that Corrales is certainly going to direct his way in the rematch.

However, Castillo said he is still going to come after Corrales the way he did in their first fight, which was contested in the middle of the ring in a space no larger than that of a phone booth. It has been referred to as one of the greatest fights in history.

“We’re going to see if we can block some of those shots, maybe just be a little more defense oriented,’ said Castillo, who is 52-7-1 with 46 knockouts. “But you’re not going to see many changes; I’m still going for the knockout.

“My punches are going to be a lot stronger, a lot more accurate, in this fight.’

Jorge Arce (40-3-1, 30 KOs) of Mexico will take on Hussein Hussein (28-2-1, 21 KOs) of Australia in a WBC interim flyweight title bout in the main undercard fight.

Carlos Hernandez (41-5-1, 24 KOs), of West Covina via El Salvador, will square off with Bobby Pacquiao (25-11-3, 11 KOs) of the Philippines in a 10-round super featherweight fight.

To top off the card, Julio Cesar Chavez Jr. (22-0, 17 KOs) of Mexico will go against Jeremy Stiers (9-4, 6 KOs) of Kansas City, Mo., in a six- round super lightweight fight.